C.S Background and Significance Undertaking research on the global demography of aging requires international collaboration, particularly for field work. Such collaboration is difficult to initiate and sustain. By promoting long-term links between the Program and international research institutions, we will provide a basis for the development of new research collaborations. We hope these collaborations lead to new research projects that can be serviced by the Program. Our aim is to develop a vibrant, mutually beneficial exchange among investigators in the Harvard and in selected countries in which we have enduring and significant ties. We plan to reinforce our Program's formal links with investigators in India and South Africa. These collaborations have been the strongest of our existing network and by concentrating our efforts on these sites we hope to build trust and significant collaboration. These linkages will benefit investigators by promoting data sharing, fostering knowledge transfer about new methodological approaches to aging research, sparking new research, and facilitating the application of evidence to public policy. Work on HIV/AIDS and LASI will encompass all four themes of the Program. For health measurement, the social determinants of health, and the economics of health, the questions to be addressed are clear. In our study of the macroeconomic implications of aging, we will not only use aggregate data but also household and individual-level data. Microeconomic data is required to understand behavioral responses to aging. In addition, we are interested in the prospect of undertaking cross country studies using comparable microeconomic data (based on census. Demographic and Health Survey, and Health and Retirement Survey data) rather than aggregate data. The pilot project proposal by Canning in Core B shows how we plan to undertake this type of approach.